Oncological outcomes following extreme oncoplastic breast conserving surgery (eOPBCS) for locally advanced breast cancer (LABC): A systematic review and meta-analysis.

Introduction: Locally advanced breast cancer (LABC) accounts for 5 % of new breast cancer diagnoses in developed countries and 30-60 % in developing regions. Historically, treatment relied on mastectomy guided by the Halstedian theory. Advances in neoadjuvant chemotherapy (NACT), breast-conserving surgery (BCS), and radiation have transformed treatment into a multimodal approach.